JP4827461B2 - Cleaning device - Google Patents

Description

  The present invention relates to a cleaning device for cleaning the surface of an image carrier of an image forming apparatus such as a printer, a copying machine, and a facsimile machine.

  As a cleaning device provided in an image forming apparatus such as a printer, a copier, or a facsimile, a cleaning device having a cleaning blade as a cleaning member for cleaning an image carrier is known.

  For example, in an image forming apparatus that employs an electrophotographic system, a toner image is formed on a photosensitive drum (image carrier) through image forming processes of a charging process, an exposure process, and a developing process, and this toner image is transferred to the image forming apparatus. Thus, the image is transferred from the photosensitive drum to a recording material (for example, paper) and an intermediate transfer member (belt or the like). In this transfer process, not all of the toner constituting the toner image on the photosensitive drum is transferred to the recording material, and a small amount of toner remains on the surface of the photosensitive drum (similarly from the intermediate transfer member to the paper). Thus, the toner remaining on the surface of the photosensitive drum (hereinafter referred to as “residual toner”) is removed by the cleaning blade.

  In recent years, electrophotographic apparatuses have become more and more colored, and at the same time, space and cost have been reduced. On the other hand, although the required performance for the cleaning blade is high, the conventional cleaning auxiliary member (spring, equalize, reciprocating, fur brush, etc.) is not used and the fixing method used only with the cleaning blade is used. In general, measures are taken to meet the required performance.

  As a conventional method of fixing the cleaning blade, it is generally known that the method can be applied to various materials and can be reduced in cost, and is a centrifugal molding method in which rubber is strip-shaped and bonded to a sheet metal. (For example, refer to Patent Document 1).

  In this way, when the cleaning blade is fixed by adhering a strip of rubber to the sheet metal, when the blade is in contact with the drum for a long time, the blade shape does not return to the original shape even if the blade is separated from the drum. There arises a problem that it is permanently deformed in the bent shape when it is in contact. In this way, the blade is permanently deformed (hereinafter, that the blade is permanently deformed or that the cleaning performance is lowered due to the blade being permanently deformed is referred to as “sag”). It has been generally said that the main cause is the influence of the adhesive layer (see, for example, Patent Document 2).

Further, in Patent Document 3, in a cleaning device in which a blade and a holding member that supports the blade are bonded, in order to prevent the blade from peeling from the holding member, the front end surface of the holding member and the holding member of the blade It is disclosed that the side surface is bonded with an adhesive. Further, it is described that the adhesive material may be a cured adhesive such as a rubber adhesive or urethane.
Japanese Patent No. 3087230 JP 2001-075452 A JP-A-60-012569

  However, regarding the problem of sag of the cleaning blade when the strip blade rubber is bonded to the sheet metal and the cleaning blade is fixed, not only the influence of the adhesive layer but also the influence of the configuration of the cleaning blade is larger. I understood that. In other words, it was found that when pressure is applied to the tip of the cleaning blade, the stress becomes a fulcrum at the contact point between the sheet metal and the rubber part, and the force causes the sag on the cleaning blade.

  Further, in the configuration described in Patent Document 3, the blade is held by adhering to the holding member, but the bonding surface between the blade and the holding member is the drum-side surface of the plate blade (outside the cleaning device). It is configured to hold from. Therefore, since the elastic member is not provided in a direction in which the blade tip is deformed when the blade comes into contact with the drum, the adhesive provided at the tip of the holding member cannot prevent sag.

  Further, there is no detailed description such as a specific shape and physical property value of the adhesive provided at the tip of the blade holding member, and a specific description for preventing blade sag as in the present invention is disclosed. It is not a thing. The adhesive provided at the tip of the holding member is obtained by curing a liquid (rubber-like) adhesive. For this reason, it is difficult to obtain the accuracy of the shape of the adhesive, and there is a problem that the cleaning property is lowered depending on the shape of the adhesive.

  Further, when various kinds of rubber materials are used for the cleaning blade in consideration of various requirements, the range of use of the rubber materials is limited in a configuration in which the influence of the adhesive must be considered.

  The present invention has been made in view of the above problems, and the purpose of the present invention is to reduce the stress concentration of the cleaning blade and the supporting member by making the contact portion of the cleaning blade and the support member face, and to generate the sag of the cleaning blade. It is an object of the present invention to provide a cleaning device capable of preventing the above and maintaining high cleaning performance over a long period of time.

The above-described problems are solved by the cleaning device according to the present invention. That is, a blade made of a plate-like rubber having a constant thickness that comes into contact with the tip of the image carrier and removes toner on the image carrier, and a support member that adheres and supports a part of the blade; The blade has a thickness of 1.5 mm or more and 4 mm or less and a free length of 3 mm or more and 15 mm or less, and the support member is a surface opposite to the surface of the blade that contacts the image carrier. In the cleaning device for adhering to a surface of the support member, the support member is provided from the tip of the support member to a surface opposite to the surface that contacts the blade of the support member, and is opposite to the surface that contacts the image carrier. The elastic member has 3 ≦ Y ≦ 12 when the Young's modulus is Y (MPa), and 1.6 ≦ B when the thickness in the blade thickness direction is B (mm). ≦ 2.5, contact with the blade When the free length direction of the length of the surface was T (mm), characterized in that it is a 0.1 ≦ T ≦ 1.5,. Alternatively, an elastic layer made of the same material as that of the blade, which is provided integrally with the blade, is provided from the tip of the support member to a surface opposite to the surface of the support member that contacts the blade. The elastic layer has a Young's modulus of Y (MPa), 3 ≦ Y ≦ 12, and a blade thickness direction of B (mm), 1.6 ≦ B ≦ 2.5, free length When the length in the direction is T (mm), 0.1 ≦ T ≦ 1.5.

  According to the present invention, in the cleaning device in which the blade is supported by the support member, the blade is supported by the support member on a surface opposite to the surface in contact with the image carrier. An elastic member that supports the base portion of the blade from the side opposite to the surface that contacts the image carrier, and the elastic member is bonded to the tip of the support member via an adhesive, so that the tip of the blade The fulcrum receiving pressure against the surface becomes a surface, stress relaxation occurs, stress concentration does not occur, blade deformation is eliminated, the blade can maintain the pressure necessary for cleaning forever, and the cleaning device can be used for a long time. High cleaning performance can be maintained.

  Embodiments of the present invention will be described below with reference to the accompanying drawings. In addition, what attached | subjected the same code | symbol in each figure comprises the same structure or effect | action, The duplication description about these is abbreviate | omitted suitably.

<Embodiment 1>
(1) Image Forming Apparatus Before describing the cleaning apparatus according to the present invention, the overall configuration and function of the image forming apparatus including the cleaning apparatus will be briefly described first.

  FIG. 1 is a longitudinal sectional view of an image forming apparatus provided with a cleaning device according to the present invention. The illustrated image forming apparatus is a laser beam printer. Hereinafter, the case where the cleaning object of the cleaning device according to the present invention is a photosensitive drum will be described as an example. However, in the present invention, the cleaning object is an intermediate transfer member such as an intermediate transfer drum or an intermediate transfer belt. It is also effective for cleaning devices.

  The laser beam printer shown in FIG. 1 includes four process units 10Y, 10M, 10C, and 10K that form toner images for each of yellow, magenta, cyan, and black, and each of the process units 10Y, 10M, 10C, and 10K. The intermediate transfer belt 13 to which the toner image is primarily transferred is provided, and the toner image multiple-transferred to the intermediate transfer belt 13 is secondarily transferred to the recording sheet P to form a full color image.

  The intermediate transfer belt 13 is formed in an endless manner, and is stretched around a pair of belt transport rollers 13a and 13b. In the process units 10Y, 10M, 10C, and 10K of the respective colors, the intermediate transfer belt 13 is rotated in a direction indicated by an arrow in the drawing. A primary transfer of the formed toner image is received. Further, a secondary transfer roller 15 is disposed at a position facing the one belt conveying roller 13a with the intermediate transfer belt 13 interposed therebetween, and the recording sheet P is in contact with the secondary transfer roller 15 and the intermediate transfer roller which are in pressure contact with each other. The toner image is inserted between the belt 13 and the secondary transfer of the toner image from the intermediate transfer belt 13.

  Also, the four process units 10Y, 10M, 10C, and 10K are arranged in parallel below the intermediate transfer belt 13, and toner images formed according to image information of each color are transferred to the intermediate transfer belt. 13 is primarily transferred. These four process units 10Y, 10M, 10C, and 10K are arranged in the order of yellow, magenta, cyan, and black along the rotation direction of the intermediate transfer belt 13, and are considered to be used most frequently. The process unit 10K is disposed at a position closest to the secondary transfer position.

  Also, below these process units 10Y, 10M, 10C, and 10K, the photosensitive drums 12 (12Y, 12M, 12C, and 12K) installed in the process units 10Y, 10M, 10C, and 10K are used as image information. A raster scanning unit 120 is provided for performing exposure accordingly. The raster scanning unit 120 is shared by all the process units 10Y, 10M, 10C, and 10K, and has four semiconductor lasers (not shown here) that emit laser light L modulated in accordance with image information of each color. And a single polygon mirror 121 that rotates at high speed and scans the four laser beams L along the axial direction of the photosensitive drum 12. Each laser beam L scanned by the polygon mirror 121 travels through a predetermined path while being reflected by a mirror (not shown here), and then passes through each scanning window 122 provided on the upper portion of the raster scanning unit 120. The photosensitive drums 12 of the process units 10Y, 10M, 10C, and 10K are exposed.

Each of the process units 10Y, 10M, 10C, and 10K includes a photosensitive drum 12, charging rollers 16Y, 16M, 16C, and 16K that charge the photosensitive drum 12 to a uniform background potential, and the laser beam. The developing devices 17Y, 17M, 17C, and 17K that develop the electrostatic latent image formed on the photosensitive drum 12 by the exposure of L to form a toner image, and the photosensitive member after the toner image is transferred to the recording sheet P A cleaning device 11 (11Y, 11M, 11C, 11K) for removing residual toner and paper dust from the surface of the drum 12 is provided so that a toner image corresponding to the image information of each color can be formed on the photosensitive drum 12. It is configured.
(2) Cleaning Device Next, details of the cleaning device 11 will be described with reference to FIG. FIG. 2 is a longitudinal sectional view showing a schematic configuration of the cleaning device 11.

The cleaning device 11 includes a frame body 21, a cleaning blade (cleaning member) 22, a waste toner conveying screw 23, and a scattering prevention sheet 24. The photosensitive drum 12 rotates in the direction of the arrow a, and the cleaning blade 22 is configured by a plate-like elastic body, is fixed to a lower portion of the frame body 21, and is positioned below the photosensitive drum 12 and installed upward. The leading end is in contact with the outer peripheral surface of the photosensitive drum 12. The scattering prevention sheet 24 is disposed upstream of the cleaning blade 22 in the rotation direction of the photosensitive drum 12, and the photosensitive drum body prevents the toner scraped off by the cleaning blade 22 from scattering in the arrow b direction. 12 is in contact.
(3) Cleaning Blade Details of the configuration of the cleaning blade 22 will be described with reference to FIG.

  FIG. 3 is a cross-sectional view showing the configuration of the cleaning blade 22. As shown in FIG. 3, in the cleaning blade 22, a strip-shaped rubber blade 3d is formed on the upper part of a sheet metal 31 that is a support member for supporting the cleaning blade 22. It is pasted. As shown in FIG. 2, the cleaning blade is supported by a sheet metal 31 on the surface opposite to the surface in contact with the drum. As a material of the rubber blade 3d, as a general material, for example, polyurethane, styrene-butadiene copolymer, chloroprene, butadiene rubber, ethylene-propylene-diene rubber, chlorosulfonated polyethylene rubber, fluorine rubber, silicone rubber, Any material can be used as long as it has an appropriate elasticity and hardness, such as an elastomer such as acrylic rubber, nitrile rubber, and chloroprene rubber. In particular, polyurethane having elasticity that does not damage the photosensitive drum 12 due to friction and high abrasion resistance is preferable. In consideration of small permanent set, a two-component thermosetting polyurethane material may be used. As the curing agent, general urethane curing agents such as 1,4-butanediol, 1,6-hexanediol, hydroquinone diethylol ether, bisphenol A, trimethylolpropane, and trimethylolethane can be used.

  The thickness t1 of the strip-shaped rubber blade 3d as a blade to be in contact with and cleaned on the image carrier is usually 1.5 mm to 4 mm, preferably 1.5 mm to 3 mm. When the thickness t1 of the rubber blade 3d is less than 1.5 mm, a pressure that exhibits the cleaning performance cannot be obtained. Further, when the thickness t1 of the rubber blade 3d exceeds 4 mm, the pressure becomes too high, and at the same time, the flexibility as the rubber material is lost and the followability to the object is lost. The free length h of the strip-shaped rubber blade 3d is 3 to 15 mm, preferably 5 to 12 mm. Moreover, when the free length h of the rubber blade 3d is shorter than 3 mm, the flexibility as rubber is lost and the followability to the object is lost. Moreover, when the free length h of the rubber blade 3d is longer than 15 mm, it is difficult to obtain a pressure that exhibits the cleaning performance.

  Next, the elastic layer (tip rubber layer) 3c at the tip of the sheet metal 31 as an elastic member constituting the gist of the present embodiment will be described.

  The elastic layer 3c as an elastic member is provided at the base portion (near the front end of the metal plate) with the metal plate 31 on the side opposite to the surface of the blade that contacts the image carrier.

  As the material of the elastic layer 3c, basically, the same material as that of the rubber blade 3d or the same material can be used. Further, the material can be changed. In the case of the same type as that of the rubber blade 3d, the adhesiveness is excellent, but the rubber blade 3d may be slightly sag with respect to the permanent set of the rubber blade 3d (effect of 1 to 2% of the whole). However, it is not an amount that reduces the effect of the present invention.

  When a material different from that of the rubber blade 3d is used as the material of the elastic layer 3c, a resin material having characteristics that can improve the sag of the rubber blade 3d can be selected although it is slightly inferior from the viewpoint of adhesion. However, in the present embodiment, it is preferable to use the same type of adhesive with emphasis on adhesion (integrity).

  Further, if the shape of the elastic layer 3c is not uniform in the longitudinal direction of the blade, it is considered that the pressure distribution of the blade is disturbed in the longitudinal direction, but the solid elastic layer 3c formed in a predetermined shape in advance. By adopting a configuration of bonding with an adhesive, the accuracy of the shape can be obtained. Basically, a resin having elasticity is basic, and is not limited to the rubber material described above.

  An index representing elasticity is Young's modulus Y. The Young's modulus according to the present invention is 3 to 12 MPa, preferably 5 to 8 MPa. When the Young's modulus is smaller than 3 MPa, the returning force to the rubber blade 3d becomes weak, and the return is weak against the sag. If the Young's modulus is greater than 12 MPa, the effect of permanent deformation of the elastic layer 3c itself appears.

  The width B of the elastic layer 3c is preferably 1.6 mm to 2.5 mm. If the width B of the elastic layer 3c is smaller than 1.6 mm, the effect of preventing sag is weak, and if it is larger than 2.5 mm, the apparatus becomes large. Further, it is preferable that the thickness of the sheet metal 31 is larger than the thickness t2. If the width B of the elastic layer 3c is smaller than the thickness t2 of the sheet metal 31, the sag of the rubber blade 3d is improved to some extent, but it is still only 1.5 times the level of the elastic layer 3c. If the width B of the sheet metal 31 is made larger than the thickness t2 of the sheet metal 31 and the resin layer 3g is formed up to the portion on the back side of the sheet metal 31, it is effective for preventing drooping. This is considered to be due to the fact that the stress locally applied to the boundary 3i where the sheet metal and the blade are bonded is alleviated by the elastic layer portion on the back side of the sheet metal.

  With respect to the sag of the rubber blade 3d, it is more than 2.54 times better when the elastic layer 3c is formed to the back side of the sheet metal than when the elastic layer 3c is smaller than the thickness of the sheet metal 31. Here, the Young's modulus was measured according to JIS K6254 (low deformation tensile test). The measurement was performed using ORIENTEC STA-1225. The shape of the test piece at the time of Young's modulus measurement was 1 (mm) × 1 (mm) × 10 (mm) (length in the tensile direction was 10 mm). The shape of the test piece is preferably the above-mentioned shape, but even if the shape changes, the Young's modulus does not change much. However, it goes without saying that the specified shape is preferable.

  The thickness t3 (or expressed as T) of the elastic layer 3c in the free length direction (direction from the fixed end side of the blade toward the free end side) is preferably 0.1 to 1.5 mm. When the thickness t3 of the elastic layer 3c is smaller than 0.1 mm, the contact with the rubber blade 3d becomes almost a point rather than a surface. When the thickness t3 of the elastic layer 3c is greater than 1.5 mm, the rubber blade 3d itself is not flexible, and stress is easily concentrated on the contact point 3i between the blade 3d and the elastic layer 3c at the tip of the sheet metal 31. It becomes difficult to disperse stress on a certain surface. Furthermore, excessively increasing the area where the blade comes into contact with the elastic layer 3c changes the stress distribution in the blade, and concentrates the pressure necessary for cleaning at the contact between the blade tip and the drum. Will not be able to.

  Here, the definition of the amount of sag is described based on FIG. 4 and FIG.

  As shown in FIG. 4A, the amount of sag is that of the cleaning blade 22 when the object is released (durable) when a certain load W (intrusion amount in the fixed system) is applied to the cleaning blade 22. The deformation amount δ (see FIG. 4B) is referred to. For example, if the penetration amount is 1.7 mm and the penetration amount is measured after 30K endurance with an electrophotographic apparatus and the value is 1.5 mm, (1.7-1.5) × 100/1. 7 = 11.7%.

  Further, as shown in FIG. 6, the intrusion amount λ is a photosensitivity in which the tip of the cleaning blade 22 (the abutting side edge portion of the free end of the cleaning blade 22 that is not deformed) enters from the virtual outer periphery of the photosensitive drum 12. The penetration depth in the radial direction of the body drum 12 (the amount entering the center of the photosensitive drum 12) is said.

  Further, based on FIG. 4 and FIG. 5, the type in which strip-shaped rubber is bonded to a conventional sheet metal and the mechanism of the blade configuration of the present invention will be briefly described.

  Normally, the cleaning blade 22 is designed to maintain a certain pressure against the photosensitive drum 12 (FIG. 4A). However, when pressure is concentrated on the tip of the cleaning blade 22, the contact point 41 between the sheet metal 31 and the rubber blade 3d becomes a fulcrum of force, stress is concentrated there, and the rubber blade 3d is permanently deformed (FIG. 4). (B)). Therefore, the cleaning blade 22 cannot maintain the pressure necessary for cleaning.

  As in the present invention, by providing the elastic layer 3c made of rubber (resin) on the upper part of the sheet metal 31 (FIG. 5A), the fulcrum receiving pressure against the tip of the rubber blade 3d becomes the surface 42, and stress relaxation occurs. Thus, no stress concentration occurs, the rubber blade 3d is not deformed (FIG. 5B), and the rubber blade 3d can maintain the pressure required for cleaning forever.

  In the present invention, the cleaning blade 22 is also effective when the rubber blade 3d of the cleaning blade 22 is in a state where it can easily be rolled. That is, as shown in FIG. 2, it is more effective to arrange the cleaning blade 22 upward. By arranging the cleaning blade 22 upward as described above, the toner is likely to accumulate on the upper portion of the sheet metal 31, and thus the toner is likely to remain up to the edge portion of the cleaning blade 22. Here, the set angle θ (contact angle: see FIG. 3) between the rubber blade 3d and the elastic layer 3c on the upper portion of the sheet metal 31 is preferably 100 ° or less. When the set angle θ exceeds 100 °, the toner easily falls along the inclination, and the toner is difficult to accumulate.

Next, the toner that is effective here will be described.
(4) Toner The toner used for developing the electrostatic latent image in the present embodiment includes a color component such as yellow, a binder resin, an aliphatic hydrocarbon-aromatic hydrocarbon having 9 or more carbon atoms. A 7 μm particle size formed of polymerized petroleum resin and wax is used.

  Conventionally known resins can be used as the binder resin. Examples thereof include polyester resin, styrene resin, styrene- (meth) acrylic resin, styrene-butadiene resin, epoxy resin, polyurethane resin, and the like.

  Such a polyester resin is synthesized from a polyol component and a polycarboxylic acid component by polycondensation. Examples of the polyol component used include ethylene glycol, propylene glycol, 1,3-butanediol, 1,4-butanediol, 2,3 butanediol, diethylene glycol, triethylene glycol, 1,5-butanediol, 1,6 -Hexanediol, neopentyl glycol, cyclohexanedimethanol, hydrogenated bisphenol A, bisphenol-A ethylene oxide adduct, bisphenol-A propylene oxide adduct and the like. As the polycarboxylic acid component, maleic acid, fumaric acid, phthalic acid, isophthalic acid, terephthalic acid, succinic acid, dodecenyl succinic acid, trimellitic acid, pyromellitic acid, cyclohexanetricarboxylic acid, 2,5,7-naphthalenetricarboxylic acid, Examples include 1,2,4-naphthalenetricarboxylic acid 1,2,5 hexanetricarboxylic acid, 1,3-dicarboxyl-2-methylenecarboxypropanetetramethylenecarboxylic acid, and anhydrides thereof.

  Further, the aliphatic hydrocarbon-aromatic hydrocarbon copolymer petroleum resin having 9 or more carbon atoms contained in the toner acts as a wax dispersion aid. For this reason, the dispersion of wax in the resin, the low-temperature fixability is maintained, the anti-offset property, the pulverization property, the image density decrease due to the charging deterioration due to the filming of the wax on the developing carrier, the filming on the image carrier The occurrence of image defects on the subject is remarkably improved. The same effect can be obtained when added to a magnetic developer. The aliphatic hydrocarbon-aromatic hydrocarbon copolymer petroleum resin having 9 or more carbon atoms includes diolefins contained in cracked oil fractions by-produced from an ethylene plant that produces ethylene, propylene and the like by steam cracking of petroleum. It is synthesized from a monoolefin as a raw material, and at least one aliphatic hydrocarbon monomer selected from isoprene, piperylene, 2-methyl-butene-1, 2-methylbutene-2, vinyltoluene, α- A copolymer obtained by copolymerizing at least one aromatic hydrocarbon monomer selected from methylstyrene, indene, and isopropenyltoluene is desirable. As the aromatic hydrocarbon monomer, it is more preferable to use a pure monomer having a high monomer purity because the odor during resin coloring and heating can be kept low.

  The purity of the aromatic hydrocarbon monomer is 95% or more, more preferably 98% or more. The aromatic hydrocarbon monomer is composed of a monomer having 9 or more carbon atoms, and in the case of a copolymer petroleum resin obtained from this monomer and an aliphatic hydrocarbon monomer, the aromatic hydrocarbon monomer having less than 9 carbon atoms and an aliphatic hydrocarbon monomer are used. Compared with a copolymerized petroleum resin obtained from a group hydrocarbon monomer, the compatibility with a binder resin, for example, a polyester resin, becomes higher.

  Further, in order to satisfy the pulverization property and heat storage property of the toner, it is preferable that the aliphatic hydrocarbon copolymer having 9 or more carbon atoms has a larger amount of aromatic hydrocarbon monomer. However, if the amount of the aromatic hydrocarbon monomer is too large, the dispersibility of the mold release agent is deteriorated. On the other hand, if the amount of the aliphatic hydrocarbon monomer is too large, the heat storage stability and the like are lowered, so the amount of the aromatic hydrocarbon monomer. The weight of the aliphatic hydrocarbon monomer is 99: 1 to 50:50, more preferably 98: 2 to 60:40, and still more preferably 98: 2 to 90:10. The amount used is 2 to 50 parts by weight with respect to 100 parts by weight of the toner binder resin. More preferably, it is 3 to 30 parts by weight. When the amount of the petroleum resin is less than 2 parts by weight, there is no effect on the wax dispersion. When the amount exceeds 50 parts by weight, the toner tends to be excessively pulverized, and the toner particle size becomes small in the developing unit and fogging occurs. As a result, the image density becomes low, and the developability may be lowered.

  Further, the degree of aggregation of the developer or toner in the present invention is measured and calculated as follows.

  The measurement was performed using a powder tester manufactured by Hosokawa Micron Corporation, a three-stage sieve in which a 200-mesh sieve, a 100-mesh sieve, and a 60-mesh sieve were sequentially stacked. As a measuring means, about 5 g of a toner or developer powder is placed on a 60 mesh sieve on the upper stage of a three-stage sieve, and a voltage of 18 V is applied to the powder tester. The weight ag remaining on the 60 mesh sieve, the weight bg of the powder remaining on the 100 mesh sieve, and the powder remaining on the 200 mesh sieve when a vibration of 7 mm and a frequency of 50 Hz was applied for 15 seconds. The degree of aggregation is calculated from the body weight cg by the following formula.

Aggregation degree (%) = (a + b × 0.6 + c × 0.2) / 5
The toner that tends to remain on the blade sheet metal preferably has a cohesion degree of 20% or more.

  Moreover, as a target to which the photosensitive member or the cleaning blade is applied, a diameter of 4 to 80 mm is preferable. If the diameter is smaller than 4 mm, there arises a problem that the rigidity of the receiving side is insufficient for the pressure of the cleaning blade. Further, if it is larger than 80 mm, it can be used, but the possibility of a blade auxiliary member or the like also arises. Therefore, the effect of reducing the space according to the present invention is diminished.

  Further, other parts will be described with reference to FIG.

Primary transfer rollers 15Y, 15M, 15C, and 15K are arranged at positions facing the photosensitive drums 12 (12Y, 12M, 12C, and 12K) of the process units 10Y, 10M, 10C, and 10K with the intermediate transfer belt 13 interposed therebetween. By applying a predetermined transfer bias voltage to these primary transfer rollers 15Y, 15M, 15C, and 15K, the photosensitive drum 12 is placed between the primary transfer rollers 15Y, 15M, 15C, and 15K. An electric field is formed, and a charged toner image on the photosensitive drum 12 is transferred to the intermediate transfer belt 13 by Coulomb force. Here, the primary transfer rollers 15Y, 15M, 15c, and 15K are configured by dispersing carbon in an elastic roller such as urethane foam, and have a resistance value of 10 ⁶ to 10 ⁸ Ωcm (measurement voltage: 100 V). The degree is preferred. In this embodiment, a conductive urethane sponge roller having a diameter of 18 mm and a resistance value of 5 × 10 ⁷ Ωcm is used as the primary transfer roller.

  On the other hand, the recording sheet P is transferred from the paper feed cassette 122 housed in the lower part of the printer housing 1 to the inside of the printer housing 1, specifically, the secondary transfer position where the intermediate transfer belt 13 and the secondary transfer roller 15 are in contact. Supplied to. A pick-up roller 18 and a paper feed roller 19 for pulling out the stored recording sheet P are juxtaposed on the upper portion of the paper feed cassette 122. A retard roller 20 that prevents double feeding of the recording sheet P is disposed at a position facing the paper feed roller 19.

  The sheet conveyance path 21 for the recording sheet P inside the printer housing 1 is provided substantially vertically along the back surface of the printer housing 1 and is pulled out from the paper feed cassette 122 located at the bottom of the printer housing 1. The recording sheet P is moved up the sheet conveyance path 21 and transferred to the toner image at the secondary transfer position, and then sent to a fixing device 123 provided immediately above the secondary transfer position. Then, the recording sheet P that has been fixed with the toner image by the fixing device 123 passes through the discharge roller 22 and is discharged in a face-down state onto a discharge tray 1 a provided on the upper portion of the printer housing 1.

  Here, the present invention will be described with specific examples.

  A cleaning blade sheet was prepared based on the formulation shown below.

Polyester polyol (trade name: Nipponporan,
100 parts by weight 4,4′-diphenylmethane diisocyanate (MDI) 41 parts by weight 1,4-butanediol 6 parts by weight After dehydrating the polyester polyol, 4,4′-diphenylmethane diisocyanate (MDI) is mixed. And a heating reaction at 115 ° C. for 20 minutes to obtain a prepolymer. 1,4-butanediol was added to this prepolymer to obtain a mixture. Using this mixture, a sheet was produced using a centrifugal molding machine. This sheet had a thickness t1 = 2 mm, a hardness of 70 ° (JIS A), and a permanent set of 0.5%. This sheet is cut into a predetermined size in the shape of a strip, and the adhesive is placed at the upper 4 mm position of the phosphate-treated iron plate (manufactured by Nippon Steel Corp., trade name: bonde steel plate). (Cemedine Co., Ltd. EP-001, 100 μm) was heat-sealed to 80 ° C. to obtain a cleaning blade. next,
Polyester polyol (trade name: Hibon,
100 parts by weight 4,4'-diphenylmethane diisocyanate (MDI) 30 parts by weight 1,4-butanediol 8 parts by weight After dehydrating the polyester polyol, 4,4'-diphenylmethane diisocyanate (MDI) is mixed And pre-polymer was obtained by heating reaction at 115 ° C. for 20 minutes. 1,4-butanediol was added to this prepolymer to obtain a mixture. Using this mixture, a sheet was produced using a centrifugal molding machine. This sheet had a thickness t3 (= thickness T in the blade free length direction) = 1 mm, a hardness of 75 ° (JIS A), a Young's modulus of 7 MPa, and a permanent strain of 1.3%. This sheet was cut into the thickness width of the sheet metal and attached to the upper part of the sheet metal with the same adhesive as described above.

  In this embodiment, the sheet as an elastic member is bonded to both the end surface of the sheet metal and the surface of the blade on the sheet metal side with an adhesive. It may be bonded to the end surface in the long direction. In order to prevent sagging, it is necessary to generate a force to push back the blade when the blade is deformed. For this purpose, at least the elastic member needs to be bonded so as not to be displaced with respect to the sheet metal. Because. At that time, the angle between the strip-shaped sheet and the rubber layer on the upper part of the sheet metal was 90 °. The thickness of the sheet metal and the width B of the elastic layer 3c were 2.0 mm.

  This manufactured blade was deformed by 1.7 mm at the tip, and was left in an environment of 45 ° C. and 90% for 5 days. After standing, return to 23 ° C, 60% environment, release 1.7mm deformation, and measure the blade tip deformation. The amount of sagging (deformation) was 2%. This blade was used in a normal electrophotographic machine to perform a cleaning test, but no cleaning defect occurred even when 50K sheets were passed. In addition, since the blade shape is upward and the toner easily collects, blade curling does not occur in a high humidity environment (Table 1).

  A blade similar to that in Example 1 was manufactured except that the rubber layer on the upper part of the sheet metal was changed to the same material as that of the blade.

Polyester polyol (trade name: Nipponporan,
100 parts by weight 4,4'-diphenylmethane diisocyanate (MDI) 41 parts by weight 1,4-butanediol 6 parts by weight The hardness of this material is 70 degrees, Young's modulus 5.3 MPa, permanent strain 0.5% Met.

  In the same manner as in Example 1, the amount of sag, poor cleaning, and blade deflection were examined. The amount of sag was 3.5%, and cleaning was 50K or more, and no problem occurred. In addition, no problem occurred with blade blades in a high humidity environment.

  A blade similar to that of Example 1 was manufactured except that the width of the rubber layer at the top of the sheet metal was covered to the back side of the sheet metal.

  In the same manner as in Example 1, the amount of sag, poor cleaning, and blade deflection were examined. The amount of sag was 1.3%, and the cleaning property was 100K or more, and no problem occurred. In addition, no problem occurred with blade blades in a high humidity environment.

  The rubber layer was previously integrally molded with a mold so that the width of the rubber layer at the upper part of the sheet metal as an elastic member was covered to the back side of the sheet metal (the side opposite to the blade bonding surface), and the integrally molded one was bonded with an adhesive. Otherwise, the same blade as in Example 2 was produced.

  In the same manner as in Example 1, the amount of sag, poor cleaning, and blade deflection were examined. The amount of sag was 1.4%, and the cleaning property was 100K or more, and no problem occurred. In addition, no problem occurred with blade blades in a high humidity environment. In this way, since the elastic member and the blade integrally molded with the mold are bonded with the adhesive, the position and shape accuracy of the elastic member portion can be increased. In addition, since the back side of the sheet metal is covered, a repulsive force of the elastic member when the blade is deformed can be obtained, which is more effective in preventing sag.

  A blade similar to that in Example 2 was manufactured except that the material of the strip-shaped sheet in Example 2 was changed to the following (see Table 1 for details).

Polyester polyol (trade name: Hibon,
100 parts by weight 4,4'-diphenylmethane diisocyanate (MDI) 41 parts by weight 1,4-butanediol 10 parts by weight The rubber material has a hardness of 78 degrees and a permanent strain of 3.0%. there were.

  In the same manner as in Example 1, the amount of sag, poor cleaning, and blade deflection were examined. Even when the hardness of the material of the blade portion was increased, the amount of sag was 1.7%, and the cleaning property was 100 K or more, and no problem occurred. In addition, no problem occurred with blade blades in a high humidity environment.

  The sheet metal upper part and the strip-shaped sheet part were integrally molded with the following materials, and the same evaluation as in Example 1 was performed.

Polycaprolactone (PCL) (trade name: Plaxel,
50 parts by weight 4,4′-diphenylmethane diisocyanate (MDI) 40 parts by weight 1,4-butanediol 4.5 parts by weight Trimethylolpropane (TMP) 2.7 parts by weight 70 parts of the above polyol (PCL) After stirring and heating at 3 ° C. for 3 hours and dehydrating, this was charged into a glass reaction vessel, and then MDI was added to the reaction vessel, followed by stirring at 70 ° C. for 1 to 2 hours in a nitrogen gas atmosphere. Was prepared.

  Separately, a curing agent (1,4-butanediol, trimethylolpropane, and the above polyol) was stirred and heated at 100 ° C. for 1 hour, dehydrated, charged into a glass reaction vessel, and the mixture was colorless under a nitrogen atmosphere. Stir and mix at 100 ° C. until clear.

  Next, the pseudo prepolymer and the curing agent were heated to temperatures shown at 60 ° C. and 40 ° C., respectively, supplied to the mixing head at a weight ratio of 10: 9, and preheated to 145 ° C. while mixing and stirring. Injection into the mold. A sheet metal is previously set at a predetermined position in the mold, and the blade is directly bonded to the sheet metal and integrally molded.

  A cleaning blade with a sheet metal thickness of 2 mm was formed. Next, the molded product was taken out from the mold and heated at 110 ° C. for 24 hours to perform secondary curing.

  As for the physical properties of the obtained cleaning blade, the detailed design conditions are as follows: the thickness of the blade portion that provides cleaning performance is 2 mm, the free length is 8 mm, and the thickness of the upper portion of the sheet metal is t3 = 0.5 mm. The width B in the thickness direction was 2 mm. Further, the physical properties of the material of the part were 71 ° (JIS A), the Young's modulus was 6.1 MPa, and the permanent strain was 0.4% because the hardness of the cleaning part and the rubber at the upper part of the sheet metal was 71 because of integral molding. The angle between the strip-shaped sheet and the rubber layer on the upper part of the sheet metal was 90 °.

  The manufactured blade was deformed at a tip of 1.7 mm and left at 45 ° C. in a 90% environment for 5 days. After standing, return to the environment of 23 ° C and 60%, release the 1.7mm deformation, and measure the deformation amount of the blade tip. The sagging amount (deformation amount) was 0.5%. This blade was used in an ordinary electrophotographic machine and a cleaning test was conducted. However, no cleaning defect occurred even when 50K sheets were passed. In addition, since the blade shape is upward and the toner easily collects, blade curling does not occur in a high humidity environment.

  As in this embodiment, by integrally forming the sheet metal, the blade, and the elastic member with a mold, the elastic member can be bonded to the front end portion of the sheet metal while improving the shape accuracy of the elastic member. Further, since the blade itself is directly bonded to the sheet metal without using an adhesive, the work process can be shortened. Further, it is possible to dispense with an adhesive.

<Comparative Example 1>
A blade similar to that of Example 1 was manufactured except that the upper layer of the sheet metal of Example 1 was not formed.

  In the same manner as in Example 1, the amount of sag, poor cleaning, and blade deflection were examined. The amount of sag was 15.0%, and the cleaning performance was about 12K. In addition, no problem occurred with blade blades in a high humidity environment.

<Comparative example 2>
A blade similar to that of Example 1 was manufactured except that the upper layer of the sheet metal of Example 5 was not formed.

In the same manner as in Example 1, the amount of sag, poor cleaning, and blade deflection were examined. The amount of sag was 20.0%, and the cleaning performance was about 5K. In addition, no problem occurred with blade blades in a high humidity environment. <Comparative Example 3>
A blade similar to that of Example 1 was manufactured except that the thickness of the rubber layer on the upper side of the sheet metal in the thickness direction of the sheet metal was half of the sheet metal width B = 1.0 (mm).

  In the same manner as in Example 1, the amount of sag, poor cleaning, and blade deflection were examined. Although the amount of sag is considerably improved, it was 7.5%, and the cleaning performance was about 20K. In addition, no problem occurred with blade blades in a high humidity environment.

<Comparative example 4>
A blade similar to that in Example 4 was manufactured except that the upper part of the sheet metal was made of a mold in the same manner as in Example 4 and the set angle with the strip portion of the blade was set to 150 °.

  In the same manner as in Example 1, the amount of sag, poor cleaning, and blade deflection were examined. The amount of sag was 5.0% because the rubber layer on the upper part of the sheet metal was uneven and the pressing force on the surface was weak. As for the cleaning property, cleaning failure occurred at about 30K. In addition, with this blade-only configuration, blade curling occurred at 5K in a high humidity environment.

<Comparative Example 5>
A blade similar to that of Example 1 was manufactured except that the thickness of the sheet metal upper rubber agent was 1.4 mm. This material had a hardness of 70 degrees, a Young's modulus of 7 MPa, and a permanent set of 1.3%.

  In the same manner as in Example 1, the amount of sag, poor cleaning, and blade deflection were examined. The amount of sag was 3.5%, and there was no problem with the cleaning performance over 50K. However, as the thickness at the Young's modulus increased, the relationship between the Young's modulus and the elastic layer thickness t3 (Equation 1) was not satisfied, and the blade was not flexible, resulting in poor cleaning.

1 is a cross-sectional view illustrating a schematic configuration of an image forming apparatus including a cleaning device according to the present invention. It is sectional drawing which shows schematic structure of the cleaning apparatus which concerns on this invention. It is sectional drawing which shows the structure of the cleaning blade of the cleaning apparatus which concerns on this invention. It is a figure explaining the amount of sag of the cleaning blade of the cleaning device concerning the present invention. It is a figure explaining the effect of the cleaning blade of the cleaning device concerning the present invention. It is a figure explaining the penetration | invasion amount (lambda) of the cleaning blade of the cleaning apparatus which concerns on this invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Image forming apparatus 3c Elastic layer 3d Rubber blade 3g Resin layer 11 Cleaning apparatus 12 Photosensitive drum (image carrier)
21 Frame 22 Cleaning blade 23 Waste toner conveying screw 24 Splash prevention sheet 31 Sheet metal B Elastic layer width h Rubber blade free length t1 Rubber blade thickness t2 Sheet metal thickness t3 Elastic layer thickness

Claims (7)

A blade made of a plate-like rubber having a constant thickness that contacts the image carrier at the tip and removes the toner on the image carrier, and a support member that supports a part of the blade by bonding. The blade has a thickness of 1.5 mm or more and 4 mm or less and a free length of 3 mm or more and 15 mm or less, and the support member is bonded to the surface of the blade opposite to the surface contacting the image carrier. In the cleaning device to
An elastic member is provided from the tip of the support member to a surface opposite to the surface of the support member that contacts the blade, and supports the blade from the opposite side of the surface that contacts the image carrier. And
When the Young's modulus is Y (MPa), the elastic member has 3 ≦ Y ≦ 12, and when the thickness in the blade thickness direction is B (mm), 1.6 ≦ B ≦ 2.5, A cleaning device characterized in that 0.1 ≦ T ≦ 1.5, where T (mm) is the length of the contact surface in the free length direction .   The cleaning device according to claim 1, wherein the elastic member is made of the same material as the blade. The cleaning device according to claim 1, wherein the blade, the support member, and the elastic member are integrally molded. 4. The cleaning according to claim 1, wherein the blade is disposed such that a tip thereof faces upward, and an angle θ at which the blade contacts the elastic member is 100 ° or less. 5. apparatus. Abuts the tip on an image carrier, comprising said image carried on the toner thickness of removing shaped fixed plate of the body blade, and a support member for supporting by bonding a portion of said blade, said The blade has a thickness of 1.5 mm or more and 4 mm or less and a free length of 3 mm or more and 15 mm or less, and the support member adheres a surface of the blade opposite to the surface contacting the image carrier. In
Provided from the tip of the support member to a surface opposite to the surface of the support member that contacts the blade, and has an elastic layer made of the same material as the blade formed integrally with the blade;
The elastic layer has a Young's modulus of Y (MPa), 3 ≦ Y ≦ 12, a blade thickness direction of B (mm), 1.6 ≦ B ≦ 2.5, and a free length direction. A cleaning device characterized in that 0.1 ≦ T ≦ 1.5, where T (mm) is the length . The cleaning device according to claim 5, wherein the blade and the support member are integrally molded. The cleaning device according to claim 5 or 6, wherein the blade is disposed such that a tip thereof is directed upward, and an angle θ formed by the blade and the elastic layer is 100 ° or less.

Images